A balloon catheter is constituted by a hollow soft tube (hereinafter referred to merely as tube) and an inflatable balloon (hereinafter referred to merely as balloon) attached to a distal end of the tube.
Such a balloon catheter is used mainly for medical purposes. Medical treatment using the balloon catheter includes, for example, PTCA (percutaneous transluminal coronary angioplasty). In PTCA, a thin wire called guide wire is inserted through to a narrowed affected area of the body, and a balloon is guided along the guide wire up the affected area, where the balloon is inflated to enlarge the affected area.
In this manner, the balloon catheter is inserted into the body of a human or animal through a blood vessel or the like, and thus need to have a smooth profile so as not to damage tissue in the body.
Generally, the balloon catheter is produced in the following manner: A cylindrical balloon is prepared which has a large-diameter body at its central portion and small-diameter portions at opposite ends of the body, and a catheter tube is inserted into each of the opposite end portions of the balloon and is welded to the end portion by applying heat, or bonded to the end portion by an adhesive.
For example, a balloon catheter manufacturing method has been known in which laser light is radiated onto the end portions of the balloon for fusion bonding (see Patent Document 1 identified below). In Patent Document 1, laser light of the far-infrared region is converged using a lens so as to impinge upon and weld the boundary between the catheter tube (tubular catheter) and the tip of the end portion of the balloon (inflatable balloon).